1. Field of the Invention
The invention relates to dyes, and in particular to dyes applied in optical recording media.
2. Description of the Related Art
With popularization of high-definition video and other multimedia formats with large file size, storage capacities of conventional recording media such as CD-R (650 MB) and DVD-R (4.7 GB), are insufficient. Next generation blue ray discs utilizes blue laser (405 nm) as read/write source, providing a mono layer storage capacity exceeding 15 GB.
In Japanese Pat. Pub. No. 200196918, coumarin derivatives are applied to serve as optical recording media dyes. The recording wavelength of the dye is 320-500 nm. When utilizing blue laser (405 nm) to record, however, its reflectivity exceeds 50%.
In Japanese Pat. Pub. No. 20022117, stilbene is applied to serve as optical recording media dye. The recording wavelength of the dye is 350-530 nm. When utilizing blue laser (405 nm) to record, its absorption coefficient (∈) is from 2.6*104 to 3.5*104.
U.S. Pat. No. 6,815,033 discloses an optical recording media dye. The recording wavelength of the dye is 350-530 nm. When utilizing blue laser (405 nm) to record, its absorption coefficient (∈) is from 1.7*104 to 4.2*104.
In U.S. Pat. No. 6,576,321, azaporphyrin metal complex dye is applied to serve as optical recording media dye. The recording wavelength of the dye is 350-500 nm. When utilizing blue laser (405 nm) to record, its carrier to noise ratio (CNR) exceeds 50 dB.
U.S. Pat. No. 6,800,347 discloses an optical recording media dye. The recording wavelength of the dye is 350-500 nm. When utilizing blue laser (405 nm) to record, its CNR exceeds 50 dB.
In U.S. Pat. No. 6,379,768, amine with conjugated double bonds is applied to serve as optical recording media dye. The recording wavelength of the dye is less than 550 nm. When utilizing blue laser (405 nm) to record, its reflectivity exceeds 60%.
Although several optical recording media dyes have been disclosed, dyes providing high thermal stability, CNR, read/write speed, and sensitivity are still called for.